39997535778 has 90 divisors (see below), whose sum is σ = 94703947371. Its totient is φ = 12615527736.

The previous prime is 39997535749. The next prime is 39997535803. The reversal of 39997535778 is 87753579993.

It can be written as a sum of positive squares in only one way, i.e., 19998767889 + 19998767889 = 141417^2 + 141417^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=141417.

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 48364201 + ... + 48365027.

Almost surely, 2^39997535778 is an apocalyptic number.

39997535778 is a gapful number since it is divisible by the number (38) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 39997535778

39997535778 is an abundant number, since it is smaller than the sum of its proper divisors (54706411593).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

39997535778 is an frugal number, since it uses more digits than its factorization.

39997535778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706 (or 851 counting only the distinct ones).

The product of its digits is 450084600, while the sum is 72.

Multiplying 39997535778 by its sum of digits (72), we get a square (2879822576016 = 1697004²).

The spelling of 39997535778 in words is "thirty-nine billion, nine hundred ninety-seven million, five hundred thirty-five thousand, seven hundred seventy-eight".